Stråvalla church dates largely from the second half of the 1200s, its plain, whitewashed walls built of natural stone in Romanesque style. The original nave and chancel arrangement was later altered when the chancel, initially flat-ended, was rebuilt with a rounded apse in 1768. It is thought the monks of nearby Åskloster may have been behind the original construction, though this remains a matter of tradition rather than firm record.
Inside, the walls carry late-medieval murals, probably painted in the early 1500s, depicting scenes from the childhood of Christ and the Passion. These were hidden for many years after the ceiling was painted over in 1872, when all but two of the old ceiling beams were sawn away. A restoration in 1964 uncovered both the wall paintings and a set of ceiling paintings from 1789, largely showing the Last Judgement, work attributed to Peter Sandell and Olof Hagström.
When the church was lengthened in the late 1760s, the new chancel was decorated by Johan Adolph Spaak. The gallery front carries thirteen painted panels showing Christ and the apostles, thought to date from the mid-1600s.
Among the church's furnishings is a Romanesque font of the late 1200s, carved from soapstone and attributed to the so-called Starrkärr workshop; it is now held by the Swedish History Museum, on loan to the Halland cultural history museum in Varberg. Fragments of a later, fourteenth-century limestone font remain in the church itself, topped by a nickel silver dish from 1889. Other older sculpted figures associated with the church, including a medieval Madonna and a figure of Saint Olaf, are kept in museum collections in Varberg and Gothenburg rather than in the church.
The timber bell tower standing near the church was built in 1739, with the present bell recast in 1948. The organ, built in 1982, incorporates the pipework front from an earlier instrument of 1852.